GENEVA: From a flawless diamond that fetched nearly 21.5 million dollars to another gem that went under the hammer for 10.9 million, Geneva's November jewellery auctions smashed several records this year.

Sotheby's chairman for jewellery in Europe and the Middle East David Bennett said the quality of sapphires, rubies and emeralds “was simply outstanding and this was reflected in the prices realised”.

Sotheby's raked in a total of 76.7 million Swiss francs ($81 million, 63 million euros) with its semiannual “Magnificent Jewels Sale”, while rival house Christies pulled in 80.6 million francs in a parallel auction.

Of the many jewels up for grabs at the Sotheby's auction was an exceptionally rare deep blue diamond that sold for $10.9 million, a world record auction price per carat.

Estimates for the diamond were between $3.5 million and $4.5 million and Sotheby's said it went to London jeweller Laurence Graff after a bidding battle.

One expert told AFP that it was clear buyers were “looking to diversify their portfolios” by investing in quality jewellery. Diamonds and gemstones also considered a safe haven by investors in tough economic times.

Many other lots reached astronomical sale prices, including a 1920s baby pink conch pearl and diamond Cartier bracelet designed for Queen Victoria Eugenie of Spain.

The bracelet sold for $3.5 million Wednesday, a record at auction and one of the highest prices ever paid for a Cartier piece, which Sotheby's described as one of the most important jewels of the last century.

Other highlights of the Sotheby's auction included a series of Burmese sapphires. One of them, a 39 carat ring-mounted gem, went under the hammer for $2.9 million, more than nine times pre-sale estimates.

Rival auction house Christie's also broke records with the sale of the flawless “Archduke Joseph Diamond” for $21.48 million on Tuesday. The price the 76-carat jewel - which once belonged to the Archduke Joseph August of Austria - fetched is a record for the auction of a clear, colourless diamond, Christie's said.

It is also the highest auction price per carat for such a gem and the record for a diamond from India's famed Golconda mines, which also produced the Koh-i-Noor that is part of the British crown jewels.

The buyer made the purchase by telephone and was not named by the auction house.